I seem to be on an XML kick lately, lol. The latest thing I've been playing around with is semantic weblog posts. This involves creating an RDF version of your blog entries to support the Semantic Web.
Basically, it involves creating an alternate format of the entry that presents the data in a structured way that is meaningful to computers, similar to RSS feeds. An example of how this can be useful is Piggy Bank, a Firefox extension that allows you to view RDF data in a nice format in your browser and do things with it.
I started with the template at HubLog, but then decided to modify it based on an article about adding more metadata with Movable Type. I made a few tweaks because of an issue with dynamically-generated pages in MT 2.661. Because I'm using MT 2.661, I used this method for dynamically generating the RDF files. The template is at "rdf" here.
Check out the finished product. To get the full effect, you would need to be using Piggy Bank in Firefox (note: what you would need to do is go to the regular entry page in Firefox and click the data coin icon in the status bar. For me, the data from the RDF file is on page 4).
Later: I made a few more modifications after looking up the RSS 1.0 specs, especially the modules. Check the template file for the latest.